Save/Load is not yet working correctly!!!

Simu base class now return NaN as pixel size.

Closes #9.

This should now be handled by the application code (e.g. CamActor).

This eliminates the dependency between ImgSrcConfig and ImgSrcGUI

Causing dependency issues otherwise. Closes #7.

if the window was hidden/minimized before.

This parameter adds a waiting time to the Acquire VI to limit the frame
rate of a simulation source.

Started to change ImgClass array type from DBL -> SGL.
It looks like that this leads to a performance boost.

Small code cleanups.